# LSI Calculator vs Thread Calculator

LSI Calculator and Thread Calculator both sit at 4.4 stars, but that hides the real split: 100% of LSI Calculator's written reviews are positive against 33% of Thread Calculator's. LSI Calculator also leads on ads (none vs shown) and update cadence (every 2 months vs every 18 months). On price, rating, ratings volume and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 4.4 for LSI Calculator against 4.3 for Thread Calculator. Both are backed by a comparable volume of ratings — 5 and 13 respectively. Written reviews are what separate them: 100% of LSI Calculator's written reviews are positive against 33% of Thread Calculator's.

LSI Calculator ships an update every 2 months, Thread Calculator every 18 months. The most recent releases landed on June 11, 2026 and September 9, 2026 respectively.

## The numbers

| Metric | LSI Calculator | Thread Calculator |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.4 (5 ratings)](https://appshunter.io/ios/app/lsi-calculator/id1233049990/reviews)** | [4.3 (13 ratings)](https://appshunter.io/ios/app/thread-calculator/id1559560290/reviews) |
| Number of ratings | 5 | **13** |
| Positive reviews | **100.0% of reviews** | 33.3% of reviews |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | **Every 2 months** | Every 18 months |
| Monetization | **Free** | Ad-supported |
| Size | 52 MB | 25 MB |
| Requires iOS | **11.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 12+ | 4+ |
| Developer | [Pure Planet Science & Technology, Inc.](https://appshunter.io/developer/1234693265) | [GSR Gustav Stursberg GmbH](https://appshunter.io/developer/1559560292) |

## What reviewers say

### LSI Calculator

[App page](https://appshunter.io/ios/app/lsi-calculator/id1233049990)

This app provides tools and educational resources to help users manage water systems, focusing on eco-friendly treatments for pools and spas. It aims to make water maintenance accessible to everyone, regardless of their experience level.

**Highlights:** Water science education, Pool and spa water management, Eco-friendly treatment guidance, NSF/ANSI Certified product information, Tools for water system management

**Features:** macOS Compatibility

**In-app purchases:** none


### Thread Calculator

[App page](https://appshunter.io/ios/app/thread-calculator/id1559560290)

This app provides a quick and easy way to calculate thread dimensions for various units, including tap hole sizes and bolt specifications. It helps metalworkers find precise measurements for internal and external threads without consulting tables.

**Highlights:** Thread cutting calculator for multiple units, Cold forming calculator, Thread repair calculator, Tap hole and bolt diameter calculation, Saves time compared to tables

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is LSI Calculator free?

LSI Calculator is free to download, with no in-app purchases.

### Is Thread Calculator free?

Thread Calculator is free to download, with no in-app purchases.

### Which has better reviews, LSI Calculator or Thread Calculator?

LSI Calculator is rated higher. LSI Calculator averages 4.4 out of 5 from 5 ratings, while Thread Calculator averages 4.3 from 13 ratings.

### Do LSI Calculator or Thread Calculator have ads?

Thread Calculator shows ads; LSI Calculator does not.

### Which is updated more often, LSI Calculator or Thread Calculator?

LSI Calculator ships an update every 2 months, and Thread Calculator every 18 months. Most recently, LSI Calculator was updated on June 11, 2026 and Thread Calculator on September 9, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*